Device used with charged pin technique for precision gas gun projectile velocity measurements

1974 ◽  
Vol 45 (4) ◽  
pp. 491-493 ◽  
Author(s):  
W. Mock ◽  
W. H. Holt
Keyword(s):  
Velocity Measurements ◽  
Projectile Velocity ◽  
Gas Gun

A Study of Damage in Aluminum Dual-Wall Structure by Hypervelocity Impact of AL-Spheres

2006 ◽  
Vol 324-325 ◽  
pp. 197-200
Author(s):  
Gong Shun Guan ◽  
Bao Jun Pang ◽  
Run Qiang Chi ◽  
Yao Zhu
Keyword(s):  
Numerical Simulation ◽  
Space Debris ◽  
Simulation Method ◽  
Hypervelocity Impact ◽  
Wall Structure ◽  
Rear Wall ◽  
Back Wall ◽  
Projectile Velocity ◽  
Gas Gun ◽  
The Law

In order to simulate and study the hypervelocity impact of space debris on dual-wall structure of spacecrafts, firstly a non-powder two-stage light gas gun was used to launch AL-sphere projectiles. Damage modes in rear wall of dual-wall structure were obtained, and while the law of damage in rear wall depends on projectile diameter and impact velocity were proposed. Finally, numerical simulation method was used to study the law of damage in rear wall. By experiment and numerical simulation of hypervelocity impact on the dual-wall structure by Al-spheres, and it is found that AUTODYN-2D SPH is an effective method of predicting damage in rear wall from hypervelocity impact. By numerical simulation of projectile diameter, projectile velocity and the space between bumper and back wall effect on damage in rear wall by hypervelocity impact, and fitting curves with simulation results, the law of damage in rear wall and dominant factors effect damage in rear wall by hypervelocity impact were proposed.

Direct display of gas‐gun projectile velocity

1977 ◽  
Vol 48 (7) ◽  
pp. 923-925
Author(s):  
I. M. Hutchings
Keyword(s):  
Projectile Velocity ◽  
Gas Gun

scholarly journals 2.2.6 Microcraters Produced by Oblique Incidence of Projectiles

1976 ◽  
Vol 31 ◽  
pp. 241-241
Author(s):  
V. Stähle ◽  
K. Nagel ◽  
E. Schneider
Keyword(s):  
Incidence Angle ◽  
Mass Range ◽  
Experimental Program ◽  
Angle Of Incidence ◽  
Iron Particles ◽  
Projectile Velocity ◽  
Gas Gun ◽  
Angle Iron ◽  
Circularity Index ◽  
The Impact

Using a Van de Graaff dust accelerator an experimental program has been carried out in order to study crater parameters as a function of projectile incidence angle. Iron particles were shot into quartz glass targets. The angle of incidence which is the angle between target normal and the impact direction of the projectile has been varied from 0° to 70° in steps of 10°. Projectile masses ranged from 10−11 to 10−13g with velocities between 3 and 20 km/sec and projectile masses at 10−2 g with 4 km/sec impact velocity using a light gas gun at the Ernst-Mach-Institut, Freiburg i.Br. The so called circularity index which is the ratio of the crater area to the area of the smallest circle around the crater is a measure of the asymmetry of a crater. The circularity index decreases linearly with increasing angle of incidence. Also a small increase of the circularity index with increasing projectile velocity has been found i.e. the craters have a rounder shape with increasing velocity at the same angle. The circularity index appears to be independent from the projectile mass in the mass range from 10−11 to 10−2 g for stainless steel targets.

Velocity Control of Diaphragmless Vertical Gas Gun for Low Pressure Ranges

2016 ◽  
Vol 715 ◽  
pp. 133-138
Author(s):  
Takahiroi Yano ◽  
Peter A. Gardiner ◽  
Yuya Egawa ◽  
Keiko Watanabe
Keyword(s):  
High Pressure ◽  
High Speed ◽  
Low Pressure ◽  
Theoretical Formula ◽  
Projectile Velocity ◽  
Gas Gun ◽  
Impact Phenomena ◽  
The Impact ◽  
Minimum Velocity ◽  
Fitting Parameters

In the field of impact engineering, high-speed impact phenomena are simulated using a projectile accelerator. At the Impact Engineering Laboratory in Ritsumeikan University, a single-stage gas gun was designed to investigate the high-speed penetration phenomena of impacts in sand, which is known to show fluid-like behavior. The gas gun consists of a 2 m launch tube that can achieve projectile muzzle velocities of up to around 500 m/s. The theoretical muzzle velocity of the projectile can be calculated by considering the speed of sound and the specific heat ratio of propellant gases. A performance evaluation for high-pressure ranges of 1 MPa and higher in a high-pressure vessel has been conducted. When fitting parameters are introduced to the theoretical formula, good agreement is obtained with the experimental results. In this study, experiments for low pressure ranges were conducted to predict the projectile velocity and to investigate the minimum velocity limit of the projectile. By introducing fitting parameters to the theoretical formula, the projectile velocity could be predicted accurately for pressure ranges less than 1 MPa. Furthermore, the minimum velocity limit of this equipment was found to be around 30 m/s.

Observation of a Critical Time Scale for Supercavitation Development and the Effect of Gas Leakage

2008 ◽  
Author(s):  
Chris Weiland ◽  
Pavlos Vlachos
Keyword(s):  
Vortex Ring ◽  
Time Scale ◽  
Critical Time ◽  
Separated Flow ◽  
Projectile Velocity ◽  
Subsequent Increase ◽  
Ambient Flow ◽  
Gas Leakage ◽  
Gas Gun ◽  
Stable Cavity

A critical time scale that describes the spontaneous growth of small stable cavities into developed supercavitation over blunt free flying cylindrical slug projectiles was observed experimentally. The projectiles were ejected using a modified gas-gun mechanism consisting of a barrel and explosive charge. Upon ignition, high pressure gases translated the projectiles down the launch barrel and into quiescent water where they were digitally imaged for analysis. Results indicate that the initially small cavities appeared downstream of the projectile forebody and grew up the projectile, partially or completely enveloping the projectile. This study introduces a mechanism to explain supercavity development over impulsively translated projectiles. As a projectile is accelerated from rest in the barrel a vortex ring is produced. Small nuclei present in the ambient flow field expand as they encounter the separated flow around the blunt forebody and become entrained in the vortex ring. The subsequent increase in vortex circulation as the projectile continues to accelerate causes the pressure in the vortex ring to drop below the Blake critical pressure, at which point the initially stable cavity rapidly grows. The small cavities grow from aft to fore as the supercavity develops, traveling at speeds up to 4 times the initial projectile velocity.

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